"”But when you look at the aggregate effects of what happens to many, many galaxies, you find something else: your overall view of the Universe gets distorted. Wherever you have a large amount of mass in one location in space — a large-scale overdensity like a galaxy cluster, cosmic filament, or something even larger — it’s going to impart large peculiar velocities, including along the line-of-sight, to every mass that’s bound to it. With many observable objects all at the same distance, but with widely-varying redshifts, mapping out objects becomes challenging."
You've heard of Hubble's law: the law that the Universe is expanding, and that the speed at which we'd infer a distant galaxy to be receding from us is proportional to its distance away from us. That "speeding away" makes the light appear redshifted, and that's what we observe.
So, measure the redshift, learn the distance, and you can map out the whole Universe, right? Not quite; here's why that isn't the way to do it!”
galaxy view 在 好大的平板還是電視？ 三星Galaxy View試用分享 - Mobile01 的美食出口停車場
Galaxy View 這台大平板的定位很微妙～一般看到一台18.4吋的大平板，腦子一定會浮現好幾個問題...--做這麼大幹嘛？--要用來取代電腦嗎？ ... <看更多>